1. Field of the Invention
This invention pertains material handling, and more particularly to apparatus that facilitates loading and unloading automotive vehicles.
2. Description of the Prior Art
Various equipment has been developed to assist loading cargo into and unloading it from motor vehicles. For example, U.S. Pat. No. 3,718,225 shows a carrier assembly for loading and transporting a rather large and heavy object, such as a snowmobile, on the rear deck of an automobile. U.S. Pat. No. 3,687,314 illustrates a dolly that rolls on the floor of a truck. A platform is hinged to the dolly. The platform may be tilted to contact the ground or to lie flat on the truck bed. U.S. Pat. No. 4,305,695 discloses a tray that rolls in and out along a frame connected to the floor of a station wagon. The bearing length of the tray on the frame is very short, thereby requiring a support prop to support the tray outer end. The container of U.S. Pat. No. 4,303,367 slides on rails attached to a station wagon floor without rollers and is therefore limited to carrying light loads.
U.S. Pat. Nos. 3,826,529; 3,471,045; 3,726,422; and U.S. Pat. No. 3,768,673 describe additional designs of racks or platforms that are slidable within a truck or other vehicle. The platforms of the aforementioned patents possess certain disadvantages that restrict their usefulness. Probably the greatest handicap of the prior retractable platforms is the limited distance beyond the end of the vehicle to which the platforms can extend. Travel in the prior equipment is limited because the cargo platforms roll along a single fixed track or guide. Another disadvantage of prior designs involves the structures for securing the movable platforms in place, both in the extended and retracted positions. For example, the designs of U.S. Pat. No. 3,471,045 and U.S. Pat. No. 3,826,472 depend on the truck tailgate to hold the retracted movable carriage or rack in place. With such a design, the truck cannot be parked with the back end sloping down hill, because the carriage or rack will dangerously roll backward immediately upon lowering the tailgate. The locking means of U.S. Pat. No. 3,726,422 employs a pin that extends into the luggage tray, where it is awkward to reach.
Thus, a need exists for improved equipment that aids loading and unloading motor vehicles.